2. If you need to ask these kinds of questions, it's best you don't write anything. Besides, if you knew anything, you would understand that the star rating system is built into mp3 files.
Wow, way to be a jerk. He doesn't know...why else would he be asking?
I guess the star rating is part of the ID3 tag. But different programs might implement that part of the tag differently, so you might look into that. I remember I once tried a program (mediamonkey I think, back in its early stages), which totally fubared all my mp3 tags.
You'll probably just use folder structures instead of WMP's library with what you're trying to do.
I'm sure there's some resource about the structure of the ID3 tag..but I wouldn't know where. Maybe try the Winamp development forums, considering how long they've been doing the whole plugin thing...I'm pretty sure they have a plugin developer's SDK, and that might help get you some info.
I'm also assuming you're using mp3 files, I have no idea how WMAs are tagged.